Haloperidol-induced neuronal apoptosis:: Role of p38 and c-Jun-NH2-terminal protein kinase

We examined patterns and mechanisms of cell death induced by haloperidol. Cortical cell cultures exposed to 10-100 muM haloperidol for 24 h underwent neuronal death without injuring glia. The degenerating neurons showed hallmarks of apoptosis, featuring cell body shrinkage, nuclear chromatin condensation and aggregation, nuclear membrane disintegration with intact plasma membrane, and prominent internucleosomal DNA fragmentation, Neither glutamate antagonists nor antioxidants prevented the haloperidol-induced neuronal apoptosis. The c-Jun-NH2-terminal protein kinase and p38 mitogen-activated protein kinase were activated within 1 h and were sustained over the next 3 h following exposure of cortical neurons to 30 muM haloperidol, Haloperidol-induced neuronal apoptosis was partially attenuated by 10-30 muM PD169316, a selective inhibitor of p38 mitogen-activated protein kinase, Inclusion of 1 mug/ml cycloheximide, a protein synthesis inhibitor, or 100 ng/ml insulin prevented activation of both kinases and subsequent neuronal death. The present study demonstrates that cortical neurons exposed to haloperidol undergo apoptosis depending on activation of p38 mitogen-activated protein kinase and c-Jun-NH2-terminal protein kinase sensitive to cycloheximide and insulin.